Historical News

Week of November 6 - 12, 2022

Fixed Site Network

​Phillipsdale Landing

The surface sonde at Phillipsdale had buoyancy issues this week, resulting in approximately 48 hours of data between November 6th and 12th where the sonde was too deep at high tide; these deep data have been excluded from the following summary. Overall, water quality at Phillipsdale Landing was fair to good this week. Weather conditions were dry for most of the week, though Friday and Saturday saw 0.79 inches of rainfall recorded at T.F. Green. Blackstone River flow remained below the 18-year daily median until these rains occurred, at which point flows increased dramatically. Salinity at the surface this week averaged 13.6 ppt and ranged from 3.3 ppt to 23.5 ppt. At the bottom, salinity averaged 22.0 ppt and ranged from 8.6 ppt to 28.2 ppt. Temperatures at the surface warmed slightly, averaging 15.4°C and ranging 12.0°C – 17.8°C. At the bottom, temperatures were like the previous week, averaging 15.5°C and ranging 13.6°C – 17.1°C.

Dissolved oxygen (DO) at Phillipsdale Landing remained above the hypoxia threshold (i.e., DO >2.9 mg/L) throughout the week. Surface DO averaged 8.1 mg/L and ranged 6.5 – 11.3 mg/L. Bottom DO concentrations averaged 6.6 mg/L and ranged from 4.6 mg/L to 10.8 mg/L, increasing over the course of the week. Surface chlorophyll became slightly elevated in the latter half of the week, reaching a maximum of 50.3 ug/L on November 11th, and averaging 8.1 ug/L overall. Bottom chlorophyll averaged 6.6 ug/L with some isolated periods of elevated readings. Please note that tidal fluctuations and Blackstone River flows greatly influence water column salinity, temperature, and DO at this location. 

Bullock Reach

Sondes were swapped for routine maintenance on the morning of November 9th. Water quality was good at Bullock Reach this week. Salinity averaged 27.0 ppt, 28.2 ppt, and 29.1 ppt at the surface, middle, and bottom sondes, respectively. Surface salinity ranged 23.4 – 28.7 ppt, mid salinity ranged 24.9 – 29.6 ppt, and bottom salinity ranged 26.6 – 30.4 ppt. Temperatures were similar to the previous week. Surface temperature averaged 15.2°C and ranged from 13.0°C to 17.3°C. Mid temperatures averaged 15.3°C and ranged from 13.8°C to 16.8°C. Bottom temperatures averaged 15.3°C and ranged from 14.3°C to 16.3°C.

DO  concentrations at Bullock Reach remained well above the hypoxia threshold all week. Surface DO averaged 8.0 mg/L and ranged 7.3 – 9.3 mg/L. In the mid waters, DO averaged 7.8 mg/L and ranged 7.2 – 8.6 mg/L. At the bottom, DO averaged 7.5 mg/L and ranged 6.2 – 8.1 mg/L. Chlorophyll concentrations were low all week (i.e., <20 ug/L). Overall, chlorophyll averaged 3.3 ug/L, 3.3 ug/L, and 2.1 ug/L at the surface, mid, and bottom waters, respectively. Isolated spikes at the surface occurred sporadically, reaching a maximum of 75.9 ug/L on November 9th, but do not appear indicative of phytoplankton bloom activity.

Week of October 30 - November 5, 2022

Fixed Site Network

Phillipsdale Landing

Sondes were swapped for routine maintenance on the morning of November 1st. Overall, water quality at Phillipsdale Landing was fair to good this week. Weather conditions were relatively dry, with just 0.05 inches of rainfall recorded at T.F. Green over the week. Blackstone River flow dropped below the 18-year daily median and declined all week. Despite the reduced freshwater flows, waters at Phillipsdale remained salinity-stratified this week. Salinity at the surface averaged 12.3 ppt and ranged from 4.3 ppt to 21.0 ppt. At the bottom, salinity averaged 23.8 ppt and ranged from 14.2 ppt to 28.3 ppt. Temperatures cooled this week compared to last, averaging 14.6°C at the surface and 15.6°C at the bottom. Surface temperatures ranged from 10.9°C to 16.6°C, while bottom temperatures ranged from 14.6°C to 16.1°C.

Dissolved oxygen (DO) at Phillipsdale Landing surface was above the hypoxia threshold (i.e., DO >2.9 mg/L) all week. Surface DO averaged 8.0 mg/L and ranged 4.9 – 10.5 mg/L. Bottom DO concentrations also remained above the hypoxia threshold all week. Bottom DO concentration averaged 5.3 mg/L and ranged from 3.7 mg/L to 7.5 mg/L. Chlorophyll generally remained low, averaging 4.9 ug/L at the surface and 5.2 ug/L at the bottom. Maximum surface chlorophyll readings reached 23.5 ug/L, recorded in the morning of November 2nd; short-duration periods of slightly elevated chlorophyll (i.e., 10 – 30 ug/L) occurred throughout the week. Please note that tidal fluctuations and Blackstone River flows greatly influence water column salinity, temperature, and DO at this location. 

Bullock Reach 

Water quality was good at Bullock Reach this week. Salinity averaged 27.2 ppt, 28.9 ppt, and 29.8 ppt at the surface, middle, and bottom sondes, respectively. Surface salinity ranged 24.4 – 29.2 ppt, mid salinity ranged 26.1 – 29.9 ppt, and bottom salinity ranged 28.2 – 30.6 ppt. Temperatures have dropped slightly compared to the previous week. Surface temperature averaged 15.3°C and ranged from 13.0°C to 16.3°C. Mid temperatures averaged 15.6°C and ranged from 15.3°C to 16.1°C. Bottom temperatures averaged 15.5°C and ranged from 15.2°C to 15.9°C.

DO concentrations at Bullock Reach remained well above the hypoxia threshold all week. Surface DO averaged 7.7 mg/L and ranged 7.0 – 8.9 mg/L. In the mid waters, DO averaged 7.3 mg/L and ranged 6.7 – 8.1 mg/L. At the bottom, DO averaged 6.8 mg/L and ranged 6.3 – 7.5 mg/L.  Chlorophyll concentrations were low all week. Overall, chlorophyll averaged 3.1 ug/L, 4.1 ug/L, and 1.4 ug/L at the surface, mid, and bottom waters, respectively. The maximum chlorophyll reading this week was in the mid-waters, reaching 10.0 ug/L on November 1st; maximum surface chlorophyll was 7.3 ug/L on the same day.

Week of January 15 - 21, 2023

Bacteria Sampling

​On January 18, twenty stations were sampled for fecal coliform bacteria in the Providence and Seekonk Rivers.  Five of these stations were also sampled for enterococci bacteria. Precipitation in the five days prior to sampling totaled 0.72 inches as recorded at TF Green.

The geometric mean of fecal coliform results for all sites was 25 MPN/100 mL compared to 21 MPN/100 mL on November 23, 2022. Overall, bacteria counts were higher in the Providence River and lower in the Seekonk River this week than during the previous sampling event on November 23. Fecal coliform counts were higher in the Seekonk River sites than in the Providence River sites (geometric means of 55 MPN/100 mL and 17 MPN/100 mL, respectively). The maximum counts (93 MPN/100 mL) were measured at Bishop Point, Phillipsdale Landing, and Narragansett Boating Center in the Seekonk River, and Point St. Bridge and India Point Park in the Providence River.

Enterococci results had an overall geometric mean of 16 MPN/100 mL. Enterococci results ranged from non-detect at Point St. Bridge to 31 MPN/100 mL at the Phillipsdale Landing site.

The table below lists the Rhode Island bacteria standards for primary contact and shellfishing established by the Rhode Island Department of Environmental Management (RIDEM). RIDEM defines primary contact as any recreational activities in which there is prolonged and intimate contact with water, involving considerable risk of ingesting water (e.g., swimming, diving, water skiing and surfing). Please note that the RIDEM bacteria standards are provided here for informational purposes only and are not intended to indicate official state compliance with primary contact or shellfishing standards.

Summary of Rhode Island Bacteria Standards for Saltwater Primary Contact and Shellfishing 
 ​
​Fecal Coli​fo​rmEnterococci
Primary Con​​​t​a​ct1​​​​​

Geome​tric me​a​n​ ≤50 MPN/1​​00​ mL
<10% ​o​f​ samples >400 MPN/100 mL

Geom​etric mean ≤35 colo​nies/100 mL
All sa​mples ≤104 colonies/100 ​​mL2

Shellfishing

Geometric mean ≤14 MPN/100 mL
<10% of samples >49 MPN/100 mL3

NO ENTEROCOCCI CR​ITERIA
1Fecal coliform primary contact criteria app​lied only when adequate enterococci data are not available; 2Single sample maximum criterion for determining beach swimming advisories at designated beaches as evaluated by the Rhode Island Department of Health; 3For a three-tube decimal dilution

Table adapted from Rhode Island Water Quality Regulations (250-RICR-150-05-1)​; see regulations for complete details.​​​​​​​​​


Week of October 30 - November 5, 2022

Water Column Profiles

​Water column profiles were conducted at six locations in the Providence River estuary using a Seabird instrument on November 2nd, 2022. In the three days leading up to the sampling event, 0.05 inches of rainfall was recorded at T.F. Green. Evidence of moderate density stratification was observed at most sites this week, with India Point Park and Edgewood Yacht Club showing signs of being strongly stratified. 
 
Surface salinities among all sites ranged from 25.6 psu at Pomham Rocks down to 11.0 psu at Edgewood Yacht Club. Bottom salinities ranged from 29.8 psu at Conimicut Point down to 24.6 psu at Edgewood Yacht Club. The warmest surface water temperature (15.9°C) was observed at Pawtuxet Cove, while the warmest bottom temperature (15.8°C) was observed India Point Park. The coolest water temperatures ranged from 14.2°C at the surface of India Point Park to 15.3°C at bottom of Bullock Reach Buoy and Conimicut Point West.

Dissolved oxygen (DO) conditions remained above the hypoxia threshold (2.9 mg/L) at all sites this week; the lowest DO observed was approximately 6.4 mg/L in the bottom waters at India Point Park. Overall, fluorescence was similar to the previous survey, with the highest values (3.05 mg/m3) observed near the surface (~1.75 m) at India Point Park. Please note numerical fluorescence data were not posted from 2020 to 2021 due to a QC issue. This issue has been resolved and fluorescence data from 2020 and 2021 will be backfilled. 

Week of October 23-29, 2022

Water Column Profiles

​Water column profiles were conducted at seven locations in the Providence and Seekonk River estuaries using a Seabird instrument on October 27th, 2022. In the three days leading up to the sampling event, 1.92 inches of rainfall was recorded at T.F. Green. Evidence of density stratification was observed at most sites this week, with Phillipsdale Landing and Edgewood Yacht Club showing signs of being well-mixed.  

Surface salinities among all sites ranged from 28.2 psu at Bullock Reach Buoy down to 20.6 psu at Point St. Bridge. Bottom salinities ranged from 30.5 psu at Conimicut Point down to 22.8 psu at Phillipsdale Landing. The warmest surface water temperature (20.9°C) was observed at Point St. Bridge, while the warmest bottom temperature (16.7°C) was observed at Edgewood Yacht Club. The coolest water temperatures ranged from 16.6°C at the surface of the Bullock Reach Buoy and Phillipsdale Landing to 16.1°C at bottom of Pomham Rocks.

Dissolved oxygen (DO) conditions remained above the hypoxia threshold (2.9 mg/L) at all sites this week; the lowest DO observed was 4.6 mg/L mid-depth at Phillipsdale Landing. Overall, fluorescence was similar to the previous survey, with the highest values (3.42 mg/m3) observed the sub-surface (<2.00 m) at Pomham Rocks. Please note numerical fluorescence data were not posted from 2020 to 2021 due to a QC issue. This issue has been resolved and fluorescence data from 2020 and 2021 will be backfilled.

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